Spectral imaging is a combination of imaging and spectroscopy where a complete spectrum is collected at every location of an image plane. This technique is sometimes called hyperspectral or multispectral imaging. Spectral imaging is not restricted to visible light but works across the electromagnetic spectrum from ultraviolet to infrared. Spectroscopy captures the entire spectrum, light intensity as a function of wavelength. Its this very detailed spectral response curve that gives spectral imaging the ability to discriminate specific chemicals and elements based upon the unique reflections and absorbances of the compound.
A mini-hyperspectral imaging device can simultaneously capture the scene on to a detector array. It can be used to create hyperspectral video with optics based on simultaneous spectral decomposition. The filter units can be built with assemblies comprising 4, 8, 16, 32, 48 filters with wavelengths interspersed and fixed at the factory. Due to limitations on detector size, camera system, cost, etc., number of filters and their wavelengths are fixed at the factory. Some of the systems acquire 16 or as high as 48 simultaneous multi-spectral images of a scene in a telecentric design. When this module is mounted in a still/video camera system, scenes can be captured at each of the peak wavelengths simultaneously so that each of the frames will contain multiple bands. More bands are considered useful since they contain more information. This means, images need to be reconstructed for additional contiguous wavelengths of interest. Simple interpolation does not give good reconstruction accuracy because of limited sampling provided by the filters.
Accordingly, what is needed in this art are increasingly sophisticated systems and methods for reconstructing a large number of wavelength bands with each band being interspersed within a band of interest to obtain a large number of bands such that the full signal of an image captured using a target hyperspectral video camera system can be generated.